These studies will examine the organization and expression of the gene(s) for b-tubulin in the aquatic fungus, Allomyces macrogynus. Tubulin composes the major portion of the meiotic and mitotic apparatus and the flagella and is involved in intra-cellular transport, in cell membrane formation and in the determination of cell shape. We will determine whether different forms of this protein have different functions or are expressed during different times of the life cycle. The organization and structure of the gene(s) will be determined by Southern blotting, cloning of the tubulin genes in either a phage or plasmid vector and use of the dideoxy nucleotide sequencing technique. The function and developmental regulation of the tubulins will be studied by isolating tubulin mutants and performing linkage and complementation analysis of them. Tubulins will be characterized on 2D gels. Developmental analysis of gene expression will also be performed by Northern blot hybridization studies. Elucidation of the genetic structure and regulation of expression of these genes will increase our understanding of the role of the cell cytoskeleton in controlling cellular differention and of how developmental processes in all organisms are controlled.